We read Nissen's recent editorial (1) on Roumie and colleagues' study (2) with great interest. We agree entirely with Nissen that the evidence base to guide clinical decision making in type 2 diabetes mellitus currently suffers from the absence of a rigorous, randomized, controlled trial (RCT) that addresses the sulfonylurea controversy. Not only are there conflicting results between older and more recent trials using sulfonylureas, but observational studies also are not concordant (2, 3). Indeed, even with the best biostatistics and methods, no epidemiologic, observational retrospective, or prospective cohort study can replace a properly conducted RCT.